Automatic train-control apparatus



Aug. 14, 1928. 1,680,999

A. LANGDON AUTOMATIC TRAIN CONTROL APPARATUS original Filed Feb. 2o, 1923 f Inventor:

o o u o 74 m Patented Aug. 14, 1928.

ineen `UNITED STATES l-A'lilei'l' @,Fliltl..

ANDREW LAGDN, 0F PRI JERVlLS, NEW' "YORK, ASSGNGR, EY MESNE ASSIGIL MENTS, TU TRLIN CNTROL OltlRATON OF AMERCA, A CRPRTIN F DELAVARE.

Application filed February 20, 1923, Serial lln applicationsvlor Letters Patent et the United States Atiled by Patrick el. lill'ord, April 17, 1922, No. 553,429, and Jan. 5, 19223, No. 610,879, a train stop systoin is described in which a primary relay on the vehicle is arranged in a conductor receiving current frein the trai'lic rail system, due to the drop in potential between the points ot contact oi' said conductor with the rail systein.

ifhe present intention relates to a priinary relay on the vehicle tor picking up current ,troni the trailie rail systein conductively, due to potential drop between the points ot contact 'with the rail system, when the current iinposed on the rail system alternating instead of direct, said relay controllingthe apparatus on the Vehicle.

ln the drawings ligure l is a diagram of a track Wiring which niay be used in connection with the present invention.

Fig. 2 is a dagrain et the present inven* tion,iwhich concerns particularly the priinary relay on the Vehicle.

The track system may be used to impose alternating current on the trailic rails in addition to that imposed tor signalling purposes, but because with the present invention signals on` the engine inay be ein ployed, itwill be understood that the invention can be carried out, it desired, in con nection with roads Whereon no roadside signalling system is installed.

Referring to a track` system which niay be used, it will be ui'iderstood by referring to ltig. l that when a train enters the block, its track relay 'lt :it is shunted and opened, and contact 2 closes. Then, it there is no train in the block ahead, `and the re y of that lblock is piclied up, and AContact 9 closed, a path o current is provided roin trans'ioriner coil. lthrough line Wire, contact 2, to the iniddle ot resistance R at 3. Here the current divides equally into the two rails and proceeds through paths Ll-G, and 5 7 to lt, Where it rennites at t3, passes through contact 9, and bach to transformer at l0.

' interference ,with the signalling track circuits at present in use is avoided by ineans olf the resistances lit and lt which are of a high enough Value to have a negligible shunting etlfect on the signalling track cir cuit. The imposed circuit voltage may be,

No. 620,283. Renewed 'December 29, 192'?.

and preferably is, from 5 to 2() tiines that ot the signalling traclr circuit Voltage. Hence the resistances R and R haveV a negligible eli'ect upon the imposed circuit-s.

It Will be understood that the traclr wiring is described as an exainpleot any suitable iorin which may be used.

li" 2 me ts the circuit" t thJ rigole iepiescn s ts o c primary relay on the engine. Due to the sinall amount ot energy received through the wheels, a separately excited relay is preferable, as being' a niuch incre rugged instrument. rilhe invention, however, is not limited in all respects to the use ol.f a separately excited relay of the :torni shown.

Two relay units connected in multiple as shown are cnnpiloyed. Si and bi are the secondm'y coils oi" these units, supplying the nlost oit the torque, and energized trein a suitable source on the engine, as described later. l? and l. are the ln'iinary coils, en,- ergized through the Wheels by any of the various connections already described heretofore in the Clil'lord applications. doth lin'iinary and secondary are energized by A. U. ot approximately the saine frequency, and contacts l and K are inade when currents in the primary and secondary circuits are not in phase. lt either circuit, priinary or secondary, is unenergized, contacts ll. and l are broken.

rlhe reason :tor the duplication ot relays new will be clear. They are dependent upon their n'iotion to close their respective contacts when the primary and secoin'lary circuits are out ot phase. rl`o obviate 'the diiticulties oit synchronizing primaries and secundarios, since theyare derived l oni entirely independent sources, thc two secondaries and Si" are suitably connecte-fd by nieans et capaeitances and reactances C and C and li and L so that they are in quadrature With cach other. when the primaries lj and l are energized, one of the two contacts l and l Will be closed.

The lo 'zal supply oit A. C. tor the secondaries may be obtained :from any suitable source. ill. sinall turbo-generator operated troni 'the stcain inains on the engine, governor controlled to give the proper lire* quency, may be used. r, as shown in the drawing, a small synchronous converter, invert-ed, operated by the engine storage battei-y, niay be used. rThis perhapsrepresents rthis insures that.

CII

Sit)

' the ideal form, since it is, when once connected, readily adjustable to proper speed. A mechanical rectifier ot suitable construction may also be used.

rThere is no necessity that the frequencies of the current'in the primary and secondary be the same, but better operation prevails when said currents are of the same trequency. Contacts K and K may be placed in the brake sclenoid controlling circuits as desired. Y

It will be understood that the vehicle will have thereon means tor causing the stopping o1c the train when both the primary relays have their contacts open; or signal means tor indicating restrictive conditions ahead when said primary relays both have their contacts open; or both stopping and signalling means may be employed to operate conjoint-ly and contr lled in a like manner by the primary relays; and whether either one or both are energized, it either or both their contacts are closed an indication will result of the conditions ahead, either by the operation or non-operation et the stopping means or the existence or non-existence of the signals, the system like that et Cliii'ord being one of continuous control. The wires O and X will connect up with the various appliances necessary to carry out the Clifford system,'all operated by direct current, such as thevarious relays and the brake controlling solenoid of that system.

it will be understood that the description and diagrams are illustrative of the invention and are not to be regarded as `restrictive upon the scope thereof which is defined by thel accompanying claims.

l claim:

'1. in train control apparatus, the combination of means for imposing an alternating current upon the tratlic rail system ot an occupied block under clear tra'tlio conditions ahead and' removing said alternating current from said occupied block under restrictive trai'iic conditions ahead, and primary relay means on the vehicle in a conductor receiving alternating current from the energized trahie rail system ot a block due to the drop in potential between the points oi contact of said conductor with said rail system, and means on the vehicle controlled by said primary relay when energized to give an indication i'or proceeding under clear traiiic conditions ahead and an indication for stopping under restrictive conditions ahead, said primary relay being excited by means on the vehicle, in addition to its excitation through said conductor substantially as described.

2. ln combination in train control apparatus, means for imposing an alternating current upon t-he traiiie rail system of an oecupied bloeit with clear conditions ahead, a primary re ay on the vehicle in a conductor receiving` said alternating current trom the said rail system due to the drop in potential between the points ot contact oit said conductor therewith, said primary relay being in duplicate units and each unit including a primary coil in, the said conductor connected therewith in multiple and each unit including also asecondary coil, said secondary coils being` -energized by alternating currents out of phase with each other, each unit also including a contact which is closed when the primary and secondary coils belonging thereto energized by currents out ot phase, and each contact opening when the primary coil belonging thereto is deenergized, and a c uit controlled by said relay units, either unit when closed maintaining a proceed indication and when both are open giving a stop indication through means in said circuit, fabstantially as described.

in combination in train control apparatus, means tor imposing an alternatingl eurreg" upon the traiiic rail system ot an occupied block with clear conditions ahead, a primary relay on the vehicle in a conductor receiving said alternating current from the said rail system due to the drop in potential between the points et contact oit said conductor therewith, said primary relay being in duplicate units and each unit including a primary coil in the said conductor connested therewith inmultiple and each unit including` also a secondary coil, said secondary coils being energized by alternating currents out ot phase with each other, each unit also including a contact which is closed when the primary and secondary coils belonging thereto are energized by currents out ot phase, and each contact opening when the primary coil belonging thereto is deenergized, and a circuit controlled by said relay units, either unit when closed maintaining a proceed indication and when both arc open giving a stop indication through means in said circuit, and means t'or insuring that the secondary coils will be energized with currents out oi phase in respect to each other.

in testimony whereof, I ai'iix my signature.

ANDREW LANGDON. 

